Richard Murray has stepped down as non-executive chairman of Charlton Athletic due to ill health.
The English businessman has been involved at boardroom level with the Addicks for the past quarter of a century.
Murray took up the role of non-executive chairman in 2014 when controversial backer Roland Duchatelet took over at the now-League One club, but has had to depart his position due to several malignant tumours in his stomach which require surgery.
Murray told Athletic's official website: "It is felt that I need to focus fully on my recovery so, with sadness, I am resigning my position as chairman of Charlton Athletic Football Club. I still have a great love for Charlton, which will stay with me always, although last season was very tough.
"I wish everyone at the club the best as we strive to get back to the Championship, and I look forward to returning to The Valley soon."
Owner Duchatelet added: "I was saddened to hear of Richard's poor health. Richard has done so much for the club and I know it was difficult for him to step down after being so intrinsically involved over the last 25 years.
"He is positive about his long-term prognosis though and all of us at Charlton look forward to seeing him back at The Valley very soon."
Charlton have kicked off their League One campaign with one point from their first two outings under Russell Slade.